1. Heredity Unit Why we are who we are . . . Kinda…
We are going to explore the process of meiosis but first we need to learn some background information. We are going to travel back to the cell.

2. Human Cells Somatic Cells: make up most of your body.
Diploid (2n) - contain 2 copies of every chromosome

3. Human Cells Gametes: are sex cells
Animals: sperm and eggs
Plants: Pollen and ova
Haploid (n) – contain 1 copy of every chromosome

4. Chromosome Vocabulary
Chromosome – entire picture
Centromere
Sister Chromatids

5. Chromosome Vocab Homologous chromosomes
Two chromosomes that have copies of the same genes

6. Autosomes: Sex Chromosome:
Chromosomes which contain the genes that do not code for the sex of an organism
Autosomes:
Sex Chromosome:
code for the sexual development of an organism

7. Review
We need to have another process that makes cells that are haploid because

8. Reason we need another process+ 46 46
Eeekk! I’m a mutant! 92

9. Solution

10. The result of Meiosis + 23 23
Gee it’s nice to be normal! 46

11. Meiosis Two Stages: Meiosis I Meiosis II
Occurs after DNA has been replicated
Divides homologous chromosomes (remember we have 2 copies of every chromosome)
Concludes with haploid cells with duplicated chromosomes
Meiosis II
DNA is not replicated
Divides sister chromatids
Ends with haploid cell(s) with single chromosome

12. Meiosis I

13. Crossing Over
Goal: increased genetic variation

14. Meiosis II

15. The final results - Gametogenesis